A helicopter for ascending or flying, in which a lifting power is generated by rapidly rotating the rotors that are provided at an upper portion of a bodywork of the helicopter, has been conventionally known. The helicopter that is equipped with two or more rotors is called as a multicopter. Patent Document 1 discloses this type of helicopter.
The multicopter of Patent Document 1 has two rotors, a coaxial contrarotating system for rotating the two rotors in the directions opposite to each other, a shaft that transmits the engine rotation to the coaxial contrarotating system and the rotors, an auxiliary propeller, a vertical tail, a horizontal tail, wheels that are driven by an electric motor, a generator and a battery that supply the electric power with a motor for a main rotor in emergency, a motor for the auxiliary propeller, the motor for the wheels, an engine that drives the main rotor and the generator, and a gearbox. Each of pitch angles of blades in the rotors is constant at all azimuth angles. The auxiliary propeller generates thrust in a front-back, left-right, and up-down directions.
The configuration of Patent Document 1 can achieve a simple configuration of a hinge of the helicopter, less failure rate, and safe flying.
Patent Document 2 discloses a rotary wing vehicle which is used as an unmanned aerial vehicle (UAV), and which flies by using rotary wings in the same way as the helicopter. The rotary wing vehicle has a main body structure having an elongated tubular spine or core, a first rotor system, a second rotor system, and a booster module. An electric power transmission to the rotor systems and between the two rotor systems is performed not by mechanical axis transmission, but mainly by electrical wiring. In the rotary wing vehicle, weight of the UAV can be reduced by falling off the booster module.
The configuration of Patent Document 2 can achieve an easy manufacturing. Moreover, weight of the UAV is reduced by falling off the booster module, which can achieve a continued flying in a second flying phase.
Non-Patent Document 1 discloses the above-described multicopter. In the multicopter of Non-Patent Document 1, the multicopter is driven with a hybrid of the engine and the motor, and thereby the engine works as a main power to concurrently generate thrust and power. The configuration of Non-Patent Document 1 can achieve a long-time continuous navigation.